Remove include only fwl.h and IWYU.

xfa/include/fwl/lightwidget/listbox.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef XFA_INCLUDE_FWL_LIGHTWIDGET_LISTBOX_H_
 #define XFA_INCLUDE_FWL_LIGHTWIDGET_LISTBOX_H_
 
 #include <memory>
 #include <vector>
 
+#include "xfa/include/fwl/basewidget/fwl_listbox.h"
+#include "xfa/include/fwl/core/fwl_error.h"
+#include "xfa/include/fwl/core/fwl_widget.h"
 #include "xfa/include/fwl/lightwidget/widget.h"
 
-class CFWL_Widget;
-class CFWL_WidgetProperties;
-class IFWL_ListBoxDP;
-class CFWL_ListBox;
 class CFWL_ListItem;
 
 class CFWL_ListBox : public CFWL_Widget {
  public:
   static CFWL_ListBox* Create();
   FWL_ERR Initialize(const CFWL_WidgetProperties* pProperties = NULL);
   FWL_ERR AddDIBitmap(CFX_DIBitmap* pDIB, FWL_HLISTITEM hItem);
   FWL_HLISTITEM AddString(const CFX_WideStringC& wsAdd,
                           FX_BOOL bSelect = FALSE);
   FX_BOOL DeleteString(FWL_HLISTITEM hItem);
@@ skipping 90 matching lines @@
   CFX_RectF m_rtItem;
   FX_DWORD m_dwStates;
   CFX_WideString m_wsText;
   CFX_DIBitmap* m_pDIB;
   void* m_pData;
   FX_DWORD m_dwCheckState;
   CFX_RectF m_rtCheckBox;
 };
 
 #endif  // XFA_INCLUDE_FWL_LIGHTWIDGET_LISTBOX_H_